fix: properly handle missing image case

Signed-off-by: Yusik Kim <[email protected]>

docling_core/types/doc/document.py

@@ -2764,18 +2764,21 @@ def _image_fallback(item: TextItem):
                             "</figure>"
                         )
 
+                img_fallback = _image_fallback(item)
+
                 # If the formula is not processed correcty, use its image
                 if (
                     item.text == ""
                     and item.orig != ""
                     and image_mode == ImageRefMode.EMBEDDED
                     and len(item.prov) > 0
+                    and img_fallback is not None
                 ):
-                    text = _image_fallback(item)
+                    text = img_fallback
 
                 # Building a math equation in MathML format
                 # ref https://www.w3.org/TR/wai-aria-1.1/#math
-                elif formula_to_mathml:
+                elif formula_to_mathml and img_fallback is not None:
                     try:
                         mathml_element = latex2mathml.converter.convert_to_element(
                             math_formula, display="block"
@@ -2792,7 +2795,7 @@ def _image_fallback(item: TextItem):
                             f"Error {err.__class__.__name__}, formula={math_formula}"
                         )
                         if image_mode == ImageRefMode.EMBEDDED and len(item.prov) > 0:
-                            text = _image_fallback(item)
+                            text = img_fallback
                         else:
                             text = f"<pre>{math_formula}</pre>"
 

test/test_export_to_html.py

@@ -0,0 +1,170 @@
+from docling_core.types.doc.base import ImageRefMode
+from docling_core.types.doc.document import DoclingDocument
+
+DOC_WITH_MISSING_PAGE_IMAGE = {
+    "body": {
+        "children": [
+            {"$ref": "#/texts/0"},
+            {"$ref": "#/texts/1"},
+        ],
+        "content_layer": "body",
+        "label": "unspecified",
+        "name": "_root_",
+        "self_ref": "#/body",
+    },
+    "form_items": [],
+    "furniture": {
+        "children": [],
+        "content_layer": "furniture",
+        "label": "unspecified",
+        "name": "_root_",
+        "self_ref": "#/furniture",
+    },
+    "groups": [],
+    "key_value_items": [],
+    "name": "2c3eaa76397e355e5132f2bee230936180583d132d3b4c28149c34e83fb87c23",
+    "origin": {
+        "binary_hash": 17809064254031518961,
+        "filename": "2c3eaa76397e355e5132f2bee230936180583d132d3b4c28149c34e83fb87c23",
+        "mimetype": "application/pdf",
+    },
+    "pages": {"1": {"page_no": 1, "size": {"height": 1754.0, "width": 1241.0}}},
+    "pictures": [],
+    "schema_name": "DoclingDocument",
+    "tables": [],
+    "texts": [
+        {
+            "children": [],
+            "content_layer": "body",
+            "label": "text",
+            "orig": "Avec la même démarche que celle suivie pour la "
+                    "description de lamplification de type Doherty on notera "
+                    "les quantités de Fourier suivantes pour la fréquence "
+                    "fondamentale",
+            "parent": {"$ref": "#/body"},
+            "prov": [
+                {
+                    "bbox": {
+                        "b": 985.3333129882812,
+                        "coord_origin": "BOTTOMLEFT",
+                        "l": 147.0,
+                        "r": 1099.0,
+                        "t": 1051.3333740234375,
+                    },
+                    "charspan": [0, 168],
+                    "page_no": 1,
+                }
+            ],
+            "self_ref": "#/texts/0",
+            "text": "Avec la même démarche que celle suivie pour la "
+                    "description de lamplification de type Doherty on notera "
+                    "les quantités de Fourier suivantes pour la fréquence "
+                    "fondamentale",
+        },
+        {
+            "children": [],
+            "content_layer": "body",
+            "label": "formula",
+            "orig": "(II.24) 2 Imar",
+            "parent": {"$ref": "#/body"},
+            "prov": [
+                {
+                    "bbox": {
+                        "b": 910.3333129882812,
+                        "coord_origin": "BOTTOMLEFT",
+                        "l": 624.3875122070312,
+                        "r": 1098.0,
+                        "t": 964.3186645507812,
+                    },
+                    "charspan": [0, 14],
+                    "page_no": 1,
+                }
+            ],
+            "self_ref": "#/texts/1",
+            "text": "",
+        },
+    ],
+    "version": "1.1.0",
+}
+
+
+def test_export_with_missing_page_image():
+    doclingdoc = DoclingDocument.model_validate(DOC_WITH_MISSING_PAGE_IMAGE)
+    actual = doclingdoc.export_to_html(
+        image_mode=ImageRefMode.EMBEDDED,
+    )
+    expected = """<!DOCTYPE html>
+<html lang="en">
+<head>
+    <link rel="icon" type="image/png"
+    href="https://ds4sd.github.io/docling/assets/logo.png"/>
+    <meta charset="UTF-8">
+    <title>
+    Powered by Docling
+    </title>
+    <style>
+    html {
+    background-color: LightGray;
+    }
+    body {
+    margin: 0 auto;
+    width:800px;
+    padding: 30px;
+    background-color: White;
+    font-family: Arial, sans-serif;
+    box-shadow: 10px 10px 10px grey;
+    }
+    figure{
+    display: block;
+    width: 100%;
+    margin: 0px;
+    margin-top: 10px;
+    margin-bottom: 10px;
+    }
+    img {
+    display: block;
+    margin: auto;
+    margin-top: 10px;
+    margin-bottom: 10px;
+    max-width: 640px;
+    max-height: 640px;
+    }
+    table {
+    min-width:500px;
+    background-color: White;
+    border-collapse: collapse;
+    cell-padding: 5px;
+    margin: auto;
+    margin-top: 10px;
+    margin-bottom: 10px;
+    }
+    th, td {
+    border: 1px solid black;
+    padding: 8px;
+    }
+    th {
+    font-weight: bold;
+    }
+    table tr:nth-child(even) td{
+    background-color: LightGray;
+    }
+    math annotation {
+    display: none;
+    }
+    .formula-not-decoded {
+    background: repeating-linear-gradient(
+    45deg, /* Angle of the stripes */
+    LightGray, /* First color */
+    LightGray 10px, /* Length of the first color */
+    White 10px, /* Second color */
+    White 20px /* Length of the second color */
+    );
+    margin: 0;
+    text-align: center;
+    }
+    </style>
+    </head>
+<p>Avec la même démarche que celle suivie pour la description de lamplification de type Doherty on notera les quantités de Fourier suivantes pour la fréquence fondamentale</p>
+<div class="formula-not-decoded">Formula not decoded</div>
+</html>"""
+    assert actual == expected